Racket



273. AMUSEMENT DEVICLS, AMt.

Search *Room C. FRITSCH RACKET File& June 29, 1936 Patented Aug. 3, 1937 -oearcn 00110 .PATENT OFFICE RACKET Charles Fritsch, Paris, France Application June 29,

1936, Serial No. 87,995

In Belgium February 28, 1936 8 Claims.

The present invention relates to rackets used in playing tennis and its object is to devise a racket whose tension is adjustable at any moment by the player himelf, without use of a key or another accessory device separate from the racket.

Rackets are known already, permitting of regulation of the tension of the diflerent strings or cords attached for this purpose in a particular way; yet this kind of regulation is tedious and delicate and moreover, while permitting of improving the tension from time to time, it excludes the interventon of the player himself for this purpose just before the start and particularly during the play.

According to the device forming subject-matter of the present invention, the regulation which is so to say instantaneous, is effectable by the player himself, even during a play, in accordance with atmospheric conditions or other circumstances and according to the adversary's kind of play.

This device is based on the observation that on increasing the tension of the longitudinal strings or upright cords neighboring the longitudinal axis, the frame of the racket gets slightly or within normal limits deformed in such manner that while the long axis gets Shortened, its smaller axis gets lengthened whereby the tension of the transverse cords increases. Hence it is sufiicient, for allowing of regulationof the net-tension, to join some longitudinal strings situated in the neighborhood of the axis, six or eight, for example, to an equal tensional system dissimulated in the handle of the racket, the player being permitted of easily actuating this system, for example by means of a bush, knob, disc or the like replacing the usual conical heel or base of the handle.

The invention also comprises simple expedients destined to guide the player with regard to the extent of the adjustment of tension and to ensure his avoiding either an excessive tension, or, inversely, a useless slackness of the net;

A particular mode of execution of the invention is described hereafter, merely in the way of example and solely with the purpose to elucidate the nature of the invention, reference being had to the accompanying drawing showing in:

Fig. 1 a diagrammatic view of a whole racket provided with the arrangement according to the invention;

Fig. 19. a device for the visual control of the cord tension;

Fig. 2 a diagrammatic view of a cord system according to a principle of the invention;

Fig. 3 one embodiment of the string tension device in a longitudinal view, partly in section;

Fig. 4 a cross view of the disconnected parts of this device, partly in section, and in Fig. 5 a transverse section according to lines Y-Y of Fig. 3;

Fig. 6, finally, shows another embediment of the string tension device.`

In Fig. 1, l represents the frame of any usual appropriate design, and 2 its handle. At 3 only the longitudinal strings neighboring the axis, and at 4 some transverse strings in the middle of the racket are represented.

By acting upon the strings 3 so as to increase their tension, the frame l gets elastically de- Iormed and particularly its inner border 5 assumes the shape indicated with dotted lines at 5a. It will be notice that the long axis of the frame gets Shortened and its small axis lengthened and that consequentlythe transverse strings 4 are tensioned. Hence it sufiices to act upon the strings 3 in order to obtain the same action on the strings 4, and for stretching the whole net it will, consequently, be sumcient to Stretch the six or eight strings situated near the axis of the racket. r

According to Fig. 2 these strings are, for the purpose stated, formed symmetrically at both parts of the long axis of the racket, instead of being individually fixed to the frame part near the handle of the racket, with their lower extremities.

This symmetrical formation is obtained by a continuous cord passing around an axle 6 situated in the handle, and an appropriate device is provided permitting of exerting a pull on said axle in a downward direction.

The whole set of the considered six or eight strings can be formed by a single cordas shown in Fig. z-arranged in a manner to slide at the upper part of the racket in holes of its frame.

These strings can be led in the following way:

First the strings 3.; and 3b are arranged by guiding the middle bent part of the cord over the axle 6 situated in a channel |2 provided longitudinally in the handle.

The branches of this cord are led through conduits Za and 2b provided in the heart of the racket and through grooves provided laterally on each side of the handle. Openings 26 establish communication of the grooves 20 with the central channel 'z and permit the passage of the cord over the axle 6.

The two branches or parts oi the cord are led into two central holes in the upper part of the frame, then bent at z, z' and led through the next neighboring upper holes so as to form two strings 3c and 3.1 passing through the conduits 2c and 24 in the heart part of the racket and led thereupon over the same axle 6.

The continuation of the string 3.1 is then introduced into a conduit 2e of the racket heart to form the upward string 3e, and the continuation of the string 3c is introduced into a Conduit 2: symmetrical to the Conduit Ze so as to form the upright string 3:.

'I'he extremities of the branches pass finally into the upper part of the frame and are fixed there at 24 and 24' in case that the tensioning net is limited to six upright cords; in case of eight upright tension cords the extremities of the cord are led downwardly at 3,; and 311 and fixed at 22 and 22'. v

Any other difierent arrangement can be of course adopted in order to ensure the repartition of the traction efforts upon a plurality of strings.

The tension device too may be executed in different ways.

One embodiment of such a device is represented in a larger scale in Figs. 3, 4 and 5.

The axle 6 guiding, as stated above, the vertical string traverses, perpendicularly to the axis, the shanks of the fork cut at the upper part of the cylindrical stem 8, and is guided by its extremities engaging grooves 21 provided in the handle, The stern 8 continues in the shape of a tube threaded inwardly at 9, and` the threaded end of a rod l l is screwed into said tube.

The whole is placed in a longitudinal cavity l2 of the racket handle, as shown in Fig. 1, and the rod ll is screwed with its lower extremity |3 into a disc or knob 14 and fastened there by the pin or pins !5. The disc l4 abuts against the lower extremity of the handle 2 through the' medium of a Washer 16 preferably of bre, and is eventually knurled or chased outwardly. On keeping the handle with one hand and on rotating the disc l4 with the other hand and in corresponding direction, the rod H will be turned owing to its attachment by pin l5 to the disc abutting against the handle itself through the medium of the Washer |6, so as to pull downwardly the tube 9 and the axle 6, the rotation of the same being prevented by its guiding in the grooves 21 of the handle. This downward pull tensions the strings 3 and consequently, as explained, the whole net.

On turning the disc |4 in the contrary direction, the tube 9 is yielding to the action of the strings, which slacken and cause slackening of the whole net.

The same result can be obtained by means of another arrangement represented in Fig. 6. According to this embodiment the threaded rod ll is replaced by a small bundle of threads I l' of metal or whipcords, led through an eye 8' provided .below the fork 1, and fixed in the endplate 14' of the racket handle.

Undulations or the like 23 are provided on the Washer !6 and on the upper surface of the knob M' so as to keep the latter in the position implied by rotation in one or in the other direction.

It is obvious that by this rotation the. threads of the bundle ll' are twisted, whereby the bundle is Shortened so that the fork 1 undergoes a traction eflort followed by tensioning of the' strings 3.

The inverse rotation slackens the bundle Il' and consequently the strings.

In order to avoid an excessive tension of the net by the player, which tension can be even dangerous, and also a slackening of the racket to an extent prejudicial to its good preservation, the arrangement of the first embodiment is such that the tensioing efiort is limited in both directions. A limitation of the tension can be obtained either by the abutment of the screw lo against the bottom of the threaded tube 8 or by the abutment of the lower extremity of this tube 8 against the upper surface of the Washer l'l.

The limitation can be established, not only in a manner to reduce the hub of the stern 8 to any desired value, but also in a manner to situate its mean position at any desired spot of the handle in its longitudinal direction. The rod ll can be devised for this purpose so as to have a variable length to permit of establishment of any desired equilibrium for the racket.

In the second embodiment, the limitation of the traction efiorts is obtained by appropriately determining the section of the threads H' and by their assembling in such a number that a tear of the bundle ensues under an efiort always inferior to the tension of rupture of the strings 3.

In both embodiments, the knob |4 may be provided with slants 23 or the like in order to mark knob positions, corresponding to the coincidence of the facets of the handle generally octagonal in its section, with the facets of the knob, while maintaining the strings tensioned. The handling is so easy in both cases that it permits of untensioning the racket after play, especially if the atmospheric conditions, such as temperature, the hygrometric state of air, and so on appear to have produced an excessive tension. It is equally possible to adjust the racket on starting the play and during the same since this adjustment can be efiected at any moment without aid of any accessory means.

The player is guided in this adjustment by the sounds emitted by the net and by the Wood, when percussed, for example, the net and the Wood with the forefinger. As is well known, the best conditions are obtained if these sounds accord with each other. In this case the adjustment is efiected by hearing.

It is also possible to secure an optical control of the adjustment, means being provided permitting the player to follow the deformations of the strings and to adjust their tension up to a degree determined by appropriate visual marks.

One, preferable, embodiment of such optical controlling system can be constituted in the following way:

A plate 30 (Fig. la) is provided on one of the lateral grooves 20 of the racket handle, this plate being transparent in its central part and `opaque in its outer portions.

To the strings 3 is adapted a travelling piece 3l, one extremity 31; whereof is red and the other 3b blue.

In the centre of the plate 30 is engraved, designed or molded a sign in transverse direction while in the centre of the travelling piece 3| the same sign, but in longitudinal direction is provided, this sign being hence situated between the colored bosses.

On slackening the strings the blue boss 3|b of the rider 3| appears below the plate 30 and the two signs of the two parts are separated from each other.

On stretching the strings by the rotation of the disc ll the sign of the rider is brought 273- AMUSEMtNl Ulvibb, uAmLo.

by little and little below the sign of the plate' until a sign is obtained indicating the appropriate tension of the strings, as visible at 32 in Fig. 11.

In this case the blue and the red boss are masked by the opaque portions of the plate.

On continuing the rotation of the disc ll the red boss 3Ia appears in the transparent part of the plate 30 and indicates the danger to be encountered on persisting in the stretching move ment.

These adjusting systems, the one by the sounds and the visual one, can furnish useful confirmation of the indications given by the tensiometer. r

These different improvements can be provided on rackets without altering their weight and equilibrium and especially without. changing their habitual aspect. r

The weight of the racket can be, indeed, reestablished by lightening the racket handle and by making the movable parts, such as the tube 8 and the axle 6, of aluminium, Duralumin or other light metal, the proper adjustment operations eected by the player modifying in no sensible way the equilibrium of the racket.

The improvements can be provided on all existing rackets.

In certain rackets, the. stem of the handle is divided in its upper half part below the heart in two portions, an empty space existing between these portions, wherein pass eventually the strings destined for the regulation of the racket tension.

In other rackets, a cut is provided between the heart and the handle, in the faces of the latter, and the strings can pass into these cuts, in the same way as into the lateral cuts shown in Fig. l. In this case the device for the verification of tension coud be placed on one of the handle faces.

It must be well understood that within th scope of the invention all modifications are possible without changing its spirit; also any suitable materials can be employed for its realize.-

tion.

It is, especially, possible to adapt the invention to all types of rackets and even to equip all existing rackets with tension device according to the invention.

The details of execution may undergo modifications. Instead of the tube, for example, forming a nut for the thread o, an outer threading can be provided on this tube and screwed into a sieeve threaded inwardly and replacing the rod ll, the disc M or any other equivalent means being in this case provided at the extremity of the sleeve.

In order to permit the strings 3 of easily following the regulating movement, any suitable accessory means may be provided.

These means can be of a nature to 'aid the sliding movement of these. strings in the frame holes of the racket, for example tubes or conduits of metal or another appropriate material, and

so on.

What I claim is:

1. In tennis rackets, a device to tension the vertical and transverse strings, sa d device comprising a longitudinal channel in the racket handle, a sliding axle disposed transversely in said channel; grooves in the handle on both sides of said channel to guide said axle during sliding and to prevent its rotation, a cord led several times over said axle and passing into eearcn HOQI several holes of the heart and at the summit of the racket frame to form a certain number of vertical strings of the central part of the racket net, the extremities of said cord being fixed to said frame while the intermediate parts of said cord slide in said frame holes and on said axle, traction means in said handle to act on said handle to stretch the vertical strings formed by said cord and to tension simultaneously the transverse strings of the net, owing to deformation of the frame.

2. In tennis rackets, a device to tension the strings, said device comprising a longitudinal channel in the racket handle, an axle disposed transversely in said channel, grooves on both sides of said channel to guide said axle during sliding and to prevent its rotation, a cord of a single piece led several times over said axle and passing into several holes of the heart and at the summit of the frame to form a certain number of the central vertical net strings, the extremities of said cord being fixed to the frame while its intermediate parts slide in the frame holes and over said axle, traction means in said handle to act on said axle to tension the vertical strings formed by said cord and, at the same time, by the deformation of said frame, to tension the transverse net strings, said traction means comprising a fork formed at the summit of a tube situated in the channel of the racket handle, two holes in the shanks of said fork to receive said sliding axle, a threading in said tube, a threaded rod to screw into said tube threading, said rod surpassing the lower border of the racket handle, a disc fixed by a pin to said rod beyond said handle and abutting against the lower border of the handle and a washer interposed between said border and said disc, to ensure that on rotating said disc at the extremity of the handle the said threaded rod is screwed in or out, to exert a pull on said iork or to release it, together with the axle and the vertical strings led over the latter.

3. In tennis rackets, a device to tension the strings, said device comprising a longitudinal channel in the racket handle, a sliding axle disposed transversely in said channel, grooves on both sides of said channel to guide said axle during sliding and to prevent its rotation, a. cord of a single piece led several times'over said axle and passing into several holes of the heart and at the summit of the racket frame, to form a certain number of vertical central net strings, the extremities of said cord being fixed to said frame whilst its intermediate parts slide in holes of said frame and over said axle, traction means in said handle and acting on said sliding axle to tension the vertical strings formed by said cord and, at the said time, to tension, owing to the deformation of said frame, the transverse net strings, said traction means comprising a tube having its upper end bifurcated, said tube being situated in said channel, two holes in the furcations of, said tube to receive said axle, a threading in said tube, a threaded rod screwed into said tube and surpassing the lower border of the racket handle, and a disc fixed by a pin to said tube, beyond said handle and abutting against the lower border of the latter, and a washer interposed between said border and said disc, to ensure that on rotating said disc at the extremity of the handle, the said tube is screwed upon or unscrewed on said threaded rod, to pull or to release the tube, the axle and the vertical strings led over said axle.

4. In tennis rackets a device for tensioning the strings, comprising a longitudinal channel in the racket handle, an axle sliding transversely in said channel, grooves in the handle on both sides of said channel to guide said axle during sliding and to prevent its rotation, a cord in a single piece led several times over said axle and passing into several holes of the heart and at the summit of the racket frame to form a certain number of vertical central strings of the racket net, the extremities of said cord being fixed to said frame while its intermediate parts can slide in holes of said frame and over said axle, traction means in said handle and acting upon said axle to tension the vertical strings formed by said cord and, at the same time, to tension, owing to the deformation of said frame, the transverse strings of said net, said traction means comprising a bifurcated member located in the channel of said handle and having an eye below the furcations, said axle being operatively connected with said furcations, cords led through said eye and attached to a disc abutting against the lower border of the racket handle, a Washer interposed between the said border and the said disc, the said Washer being fixed to the handle and being provided with sinuous knurls, the said disc comprising sinuous knurls corresponding to the knurls of said washer, to ensure that on rotating said disc the said threads or cords are twisted and that said disc guards its position owing to engagement of the sinuosities of the disc and Washer, the threads or cords exerting, on being twisted, a traction upon the bifurcated member, the axle and the vertical strings led over said axle.

5. In tennis rackets, a device for tensioning the strings, said device comprising a longitudinal channel in the racket handle, a sliding axle disposed transversely in said channel, slits in said handle on both sides of the channel to guide said axle during sliding and to prevent its rotation, a cord formed of a single piece, said cord being led several times over said axle and passing into several holes of the heart and at the summit of the racket frame to form a. certain number of vertical strings disposed centrally in the net of the racket, the extremities of the said cord being fixed to the said frame while its intermediate parts can slide in the holes of the said frame and over the said axle, traction means situated in the said handle and acting upon the said axle in order to tension the vertical strings formed by the said cord and, at the same time, to tension the transverse strings owing to the deformation of the said frame and means to limit the tension of the said vertical strings.

6. In tennis rackets 'a device to tension the strings, comprising a longitudinal channel in the racket handle, a sliding axle disposed transversely in said channel, grooves in said handle on both sides of the said channel, to guide said axle during sliding and to prevent its rotation, a cord formed of a single piece, led several times over said axle and passing into several holes of the heart and at the summit of the racket frame, to

form a certain number of vertical central cords in the net of the racket, the extremities of the said cord being attached to the said frame while its intermediate parts can slide in the holes of said frame and over said axle, traction means in said handle and acting upon said sliding axle to tension the vertical strings formed by said cord and, at the same time, the transverse strings of the said net owing to the deformation of the frame, said traction means comprising a fork formed at the summit of a tube, situated in the channel of the racket handle, two holes in the shanks of said fork to receive the said sliding axle, a threaded rod to screw into an inner thread of said tube and to surpass the lower border of theracket handle, a disc fixed by a pin to said rod beyond the handle and abutting against the lower border of the latter, a Washer between said border and said disc, to ensure that on rotating said disc the said threaded rod is screwed in or out to pull or to release the fork, the axle and the vertical strings led over said axle, and means to limit the tension and the slackening of said vertical strings, said means being constituted by abutments on the tube of the fork and on said threaded rod to limit the extent of screwing or unscrewing of these parts.

7. In tennis rackets, a device to tension the strings, comprising a longitudinal channel in the racket handle, a sliding axle disposed transversely in said channel, grooves in the handle on both sides of said channel to guide said axle during sliding and to prevent its rotation, a cord of a single piece led several times over said axle and passing into several holes of the heart and at the summit of the racket frame to form a certain number of vertical strings centrally in the racket net, the extremities of said cord being fixed to said frame while its intermediate parts can slide in the holes of the frame and on said axle, traction means in said handle and acting upon said axle to tension the vertical strings formed by said cord and, at the same time, owing to the deformation of the frame, the transverse strings of the net, said traction means comprising a bifurcated member Situated in the channel of the racket handle, holes in the furcations of said bifurcated member to receive the said sliding axle, a thread on said bifurcated member, another member threaded to said bifurcated member, said other member surpassing the lower border of the racket handle, a disc fixed to said other member by a pin and beyond said handle, said disc abutting against the lower border of the latter, a Washer between said border and said disc, to ensure that on rotating said disc the said bifurcated member is moved to pull or to release the bifurcated member, the axle and the vertical strings led over said axle, and means to limit the tension and the slackening .of said vertical strings, said means being constituted by abutments on said bifurcated member and said other member to limit the extent of screwing or unscrewing of these parts.

8. In tennis rackets, a device for tensioning the strings, comprising a longitudinal channel in the handle, a transverse axle in said channel, grooves in said channel to guide said axle during sliding and to prevent its rotation, a cord led several times over said axle and passing into several holes in the heart and at the summit of the frame to constitute a certain number of vertical strings in the centre of the net, the ends of said cord being fixed to said frame and its intermediate parts being permitted of sliding in the holes of the frame and over said axle, traction means in said handle and acting upon said axle to tension said vertical strings and, by the deformation of the frame, the transverse strings of the net, said traction means comprising a fork in the handle, a-staple below said fork, threads or cords passing through said staple and attached to a disc abutting against the lower border of the handle, a Washer between said border and said disc, said Washer being fixed to the handle and being pro- 273. AMUSEMENT DEVICES, GAMES.

vided with grooves, corresponding countergrooves on said Washer to engage said disc grooves and to keep the disc in the position imparted to it, said threads or cords exerting when twisted, a, traction upon the fork, the axle and the vertical strings led over said axle, and means to limit the tension of the said vertical strings, said Search Boom means consisting in giving said threads or cords a total traction resistance less than the traction resistance of the said vertical strings, to ensure the rupture of said threads or cords previous to the rupture of said strings.

CHARLES FRITSCH. 

